getDragGridSize function

Size getDragGridSize({ required int total, required Size viewSize, required double? mainAxisExtent, required double childAspectRatio, required double crossAxisSpacing, required double mainAxisSpacing, required int crossCount, required Axis direction, })

Computing Drag Grid Size

Implementation

Size getDragGridSize({
  required int total,
  required Size viewSize,
  required double? mainAxisExtent,
  required double childAspectRatio,
  required double crossAxisSpacing,
  required double mainAxisSpacing,
  required int crossCount,
  required Axis direction,
}) {
  int line = 1;
  double width = 0.0;
  double height = 0.0;
  double ctxWidth = viewSize.width;
  double ctxHeight = viewSize.height;

  line = (total ~/ crossCount);
  line += (total % crossCount > 0 ? 1 : 0);

  if (direction == Axis.vertical) {
    width = (ctxWidth - crossAxisSpacing * (crossCount - 1)) / crossCount;

    if (mainAxisExtent == null) {
      height = width / childAspectRatio * line + mainAxisSpacing * (line - 1);
    }

    if (mainAxisExtent != null) {
      height = mainAxisExtent * line + mainAxisSpacing * (line - 1);
    }

    return Size(
      max(ctxWidth, 0),
      max(height, 0),
    );
  }

  if (direction == Axis.horizontal) {
    height = (ctxHeight - crossAxisSpacing * (crossCount - 1)) / crossCount;

    if (mainAxisExtent == null) {
      width = height / childAspectRatio * line + mainAxisSpacing * (line - 1);
    }

    if (mainAxisExtent != null) {
      width = mainAxisExtent * line + mainAxisSpacing * (line - 1);
    }

    return Size(
      max(width, 0),
      max(ctxHeight, 0),
    );
  }

  return Size.zero;
}